How Cell Phone Jammers Work

Alternatives to Cell Phone Jamming

While the law clearly prohibits using a device to actively disrupt a cell-phone signal, there are no rules against passive cell-phone blocking. That means using things like wallpaper or building materials embedded with metal fragments to prevent cell-phone signals from reaching inside or outside the room. Some buildings have designs that block radio signals by accident due to thick concrete walls or a steel skeleton.

Companies are working on devices that control a cell phone but do not "jam the signal." One device sends incoming calls to voicemail and blocks outgoing calls. The argument is that the phone still works, so it is technically not being jammed. It is a legal gray area that has not been ruled on by the FCC as of April 2005.


Cell-phone alerters are available that indicate the presence of a cell-phone signal. These have been used in hospitals where cell-phone signals could interfere with sensitive medical equipment. When a signal is detected, users are asked to turn off their phones.

For a less technical solution, Coudal Partners, a design firm in Chicago, has launched the SHHH, the Society for HandHeld Hushing. At its Web site, you can download a note to hand to people conducting annoying cell-phone conversations, expressing your lack of interest in what they're talking about.

For more information on cell-phone jamming and related topics, check out the links below.

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More Great Links


  • CTIA: Estimated Subscribers
  • FCC: Blocking & Jamming
  • AMTA: Cell phone jammers or blockers dangerous and illegal
  • Daily Sun: Cell Phone Detectors and Jammers
  • ExtremeTech: Disruptive Tech Gets Scary,1558,1706725,00.asp
  • Engadget: Black-market cellphone jammers selling fast
  • New York Post Online: Shut the Cell Up
  • Churches Installing Cell Phone Jammers
  • They Be Jammin' in France
  • Tech Policy: Cell Phone Jammers: A Great Technology and Policy Case Study
  • Mike's List: Cell Phone Wars!
  • TechWorthy: The Jammers Debate
  • PCWorld: French Cinemas Silence Cell Phones,aid,118132,00.asp
  • France says "Oui" to cellphone jammers
  • The No-Phone Zone
  • BBC News: French cinemas act to jam mobiles
  • The Best Security Doesn't Always Begin at Home
  • Ten O'Clock Tech: Mobile-Phone Disruptions
  • Slate: Hope You Like Jamming, Too
  • NNS: Cell Phone Jammers, Illegal in U.S., Can Create Silent Zones